I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Sherlock breaks into a crime scene. The victim is the owner who is slumped dead on a chair and have a bullet hole in his head. A gun lies on the floor and a cassette recorder is found on the table. On pressing the play button, Sherlock hears the message 'I have committed sins in my life and now I offer my soul to the great Lord' and followed a gunshot Sherlock smiles and informed the police that's its a murder.

Why did he think so?

Spot 5 differences in two Christmas tree below:

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

What is 3/7 chicken, 2/3 cat and 2/4 goat?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

You walk into a creepy house by yourself. There is no electricity, plumbing, or ventilation. Inside you notice 3 doors with numbers on them. Once you open the doors you will die a particular way. Door No.1 You’ll be eaten by a lion who is hungry. Door No.2 You’ll be stabbed to death. Door No.3 There is an electric chair waiting for you. Which door do you pick?

The more it dries, the wetter it becomes. Can you tell what it is?

Can you count the number of triangles in the given picture?

Why Aeroplane windows are round?